Conventional driveline systems typically include tubeshaft assemblies for delivering torque from a driving system, such as a motor or engine to a driven system, such as wheels or power equipment. Typically, these shafts have been made from a steel, aluminum or composite material having connection devices such as a constant velocity joint or other joint end mounting attached thereto
Composite drive/shafts offer excellent strength-to-weight and stiffness-to-weight ratios compared to metallic driveshafts. Their coefficients of thermal expansion are generally low, which reduces the load on couplings and hanger bearings caused by thermal excursions. These drive shafts play an increasingly important role in today's air and automotive drivetrain industries, which are constantly seeking ways to increase strength while reducing the gross weight of the vehicle. Composite driveshafts have found many applications in the design of drivetrain systems for the reduction of wear and improved strength.
However, composite driveshafts require metallic adapters for interfacing other shaft components to transmit loads. In general, composite tubeshafts are typically made by weaving composite thread around a shaft mandrel, adding resin and curing. The created tube is then machined to create a desired interlock configuration and a joint end is slid into the end of the shaft and is locked into place by a securing collar or wrapping more composite around the joint end and repeating the curing process. Another common method is to wrap the composite thread around a shaft mandrel with the joint end in place or to insert the joint end onto the end of the finished composite shaft and wrapping additional composite material around the joint end to secure it to the composite shaft. Generally, multiple types of composite-adapter joint end systems are employed for composite driveshafts: notched (cutouts at the end of the shaft with corresponding raised features on a joint end), notched with retaining collar, press-fit (either internal or external), lugged (joint end includes lugs surrounded by composite then cured in place), bonded joints (joint end is placed in tube and additional composite is wrapped around to create a bond after curing) and bonded joints with ribs (joint end is placed in tube prior to curing). These designs are limited by their structural integrity, weight, or manufacturing costs and complexity.
Therefore, what is needed is an integrally fabricated encapsulated connection for a tubeshaft metallic interface end and a method for providing same that is low cost, lightweight and high strength.